Clinical diagnostic analyzers are being developed with increasing levels of complexity and sophistication in order to fully automated the performance of chemical assays and immunoassays of biological fluid samples such as urine, blood serum, plasma, cerebrospinal liquids and the like, these fluid samples almost universally being contained in open or capped sample tubes. Generally, chemical reactions between an analyte in a patient's biological sample and reagents used during performing the assay result in generating various signals that can be measured by the analyzer. From these signals the concentration of the analyte in the sample may be calculated.
A wide variety of automated chemical analyzers are known in the art and are continually being improved to increase analytical menu and throughput, reduce turnaround time, and decrease requisite sample volumes. See for example, U.S. Pat. Nos. 6,103,193, and 6,027,691 and 5,482,861. Such improvements, while necessary in themselves, may be hampered if sufficient corresponding advances are not made in the automation of pre-analytical sample preparation and handling operations like sorting, batch preparation, centrifugation of sample tubes to separate sample constituents, cap removal to facilitate fluid access, and the like.
Automated sample pre-treatment systems generally include the use of conveyor systems for conveying specimens to analyzers, such as those described in U.S. Pat. Nos. 5,178,834, and 5,209,903. Typical of such systems, a sample is transported to an analyzer by a primary conveyor and either removed from the primary conveyor by a robotic-like device and placed into a sampling area of an adjacent analyzer or may be shuttled onto an analyzer-specific conveyor that transports the sample to the sampling area of an adjacent analyzer. In the later instance, when sufficient sample aliquots have been removed from the sample, the sample is returned to the primary conveyor and transferred thereto from the analyzer-specific conveyor.
As automated clinical chemistry sample handling workstations become increasingly complex, the number of instances wherein samples interfere with one another during transportation processes also increase. Clearly, a problem to be avoided is any form of interference between the sample transferring from the analyzer-specific conveyor with samples already on the primary conveyor and being transported thereby.
U.S. Pat. No. 6,019,945 discloses a transfer mechanism for transferring a sample container holder between a conveyor line and a sampling area formed in each of several analyzers, the transfer mechanism being connectable to each one of the plurality of analyzers. At least two analyzers units are different from one other in either the types of reagent supply means, the number of analysis items that can be analyzed, the number of tests that can be processed in a unit time, or the species of samples to be processed.
U.S. Pat. No. 5,087,423 discloses a plurality of analyzing modules, a plurality of analyzing routes and at least one bypass route bypassing at least one analyzing module are arranged. Each analyzing module is capable of analyzing samples with respect to one or more items, and samples successively supplied from the introduction sides of the modules are selectively delivered into each module.
U.S. Pat. No. 6,060,022, automatically presents pre-treated samples in open containers to robotic devices operated in conjunction with independent stand-alone analyzers. In order to provide precise and accurate handling of the sample tubes, it is critical to position and align the tubes within a sample tube carrier accurately so that the various robotic handling devices may automatically and consistently remove or replace tubes from tube carriers as needed.
Although these prior art systems have advanced sample handling and processing throughput, what has not been addressed is the challenge of replacing a sample onto a moving conveyor belt while the belt is conveying other samples without adversely affecting either of the two samples.